The current trend toward the use of household electrical apparatus and appliances characterized by automatisms includes the elimination of manual preliminary set-up operations and, in particular, the elimination of those manual operations of filling the dispenser of certain appliances with detergents and other substances every time the appliance has to be used. Specifically, automatic devices now control such filling operations.
At present, dishwashing machines feed the washing tank with powder or liquid detergents by means of a conventional detergent dispenser connected with the tank and divided into various separate and independent compartments each one of them containing a respective detergent.
The different compartments of the dispenser are filled with predetermined doses of powder or liquid detergents which are then directly or indirectly removed from the compartments by water flowing to the washing tank.
The dispensing devices presently employed in the case of powder detergents are of the single-dose type wherein the user, before every washing cycle, must fill a special tray with detergent which then, through a signal command issued by an appropriate control device (programmer), is introduced into the washing tank so as to be dissolved in the washing water.
These devices are rather reliable and simple but they require the user to fill the dispenser before every washing cycle.
Further, the filling operation requires a great amount of attention because the occurrences in which the amount of detergent is incorrect, and often excessive, are quite frequent. Obviously, erroneous amounts of detergent result in a loss of money as well as a greater pollution of the drained water.
Furthermore, when using a dishwashing machine, it is necessary, as a rule, to open its door completely and fill the dispensers located at the inner side of the door. Thus, the user must bend almost down to the floor with a considerable discomfort and also, especially in the case of aged persons, with a great amount of effort.
Washing machines equipped with means for accommodating large amounts of detergents, particularly liquid detergents, are well-known in the art.
These prior art means consist essentially of a plurality of high capacity rigid containers capable of holding liquid substances and connected with the washing tank through respective conduits, the latter being provided with volumetric pumps.
Although these rigid containers satisfactorily dispense liquid detergent or liquid detergent components to the washing tank of the machine, then are so large that, as a rule, they cannot be provided inside the washing machine. Rather, these containers must be disposed outside of the machine.
In fact, washing machines and dishwashing machines in which reservoirs of liquid substances are provided outside of the machine, preferably as assembled together as a container disposed side-by-side with the machine, are well-known in the prior art.
The height and depth of such prior art containers correspond, as a rule, to those of the machine itself so as to comply, at least in part, with the existing dimensional standards.
However, this type of detergent dispenser has two disadvantages. First of all, it takes up additional room which is limited, especially in modern houses. Secondly, it requires the use of detergents in liquid form which, at the present time, are still less effective and more polluting than detergents in powder form.
Further, each of the different washing programs, set by the manufacturer, may typically call for different amounts of detergents, and such "to size" dosage is not obtainable with the current single-dose detergent dispensers.